In a recent article, we dove into food variety, its role, and the long-term impact that it can have on our body composition and eating habits. A higher food variety acts as a double-edged sword in that, depending on the type of foods we’re obtaining variety from, it can lead us to eat in excess and gain unnecessary body fat over time. Check out that article here.
A key player in why a wide food variety can have such detrimental effects on our eating behaviors stems from something known as sensory-specific satiety.
What is Sensory-Specific Satiety?
Sensory-specific satiety (SSS) is a satiation mechanism defined as, “the decline in pleasantness of the flavor of a specific food that has just been eaten in contrast to other non-consumed foods.” In other words, as we continuously eat a particular food item, our desire to eat that same food item should diminish over time.
The relationship between SSS and food variety is not unheard of either. So, since sensory-specific satiety is specific for eaten foods/snack items, when we have such a high variety of foods available to us (i.e. our current food environment), it can take longer for us to feel satiation from all of these foods. This, in turn, leads to a greater total caloric intake.
Increased Stimulation = Increased Intake
A study was conducted in order to learn more about the relationship that exists between sensory-specific satiety and a wide food variety. Researchers wanted to create a design using ‘fast food’ type meals and condiments, since these more hyperpalatable meals are thought to play a larger role in increased food intakes and the rise of obesity as a whole.
21 males were put through 3 randomized sessions over a span of 3 weeks (1 session per week). Each session consisted of having the men eat a 2-course meal consisting of fries and brownie cakes – with or without condiments. (Side note: sign me up).
What differed between each of these sessions was the way in which their meals were presented to them. The sessions were designed as follows:
- The “monotonous” session – the two courses (fries and brownies), were offered without condiments and each was eaten ad libitum (in other words, as much as the subjects wanted).
- The “successive” session – fries were offered first without condiments, then fries with one of the condiments, and finally fries with the other condiment were offered. Each condiment was offered once the subject finished eating the preceding food. This same procedure was repeated for the brownie cakes in the second course.
- The “simultaneous” session – both condiments were made freely available to the subjects during the entirety of each course (also eaten ad libitum).
Throughout these sessions, the subjects were given subjective ratings in order to assess their flavor-pleasure ratings (food’s pleasantness before and following courses), hunger, olfactory evaluations (sense of smell and perceived pleasure regarding foods/condiments), and their reasons for terminating each course when they did.
Sensory Satiety Disruption
The total amount of food eaten and even the duration of each course was shown to differ depending on the session. The total food intake was 40% and 35% higher on average in the simultaneous and successive sessions, respectively, than the monotonous session. Total caloric intake was shown to be about 41% and 24% greater for the simultaneous and successive sessions than in the monotonous one as well.
A lot can be said for the perceived pleasantness as each course went on. As expected, when considering the concept of sensory-specific satiety, flavor-pleasure ratings for each course did decrease after ad libitumingestion. So, as those meals went on the subjects got tired of those flavors and sensations or full, and subsequently terminated their meals. However, after presenting the meal’s first condiment (ketchup for the fries, vanilla cream for the brownies), this triggered the subjects to resume their eating further.
Essentially, the addition of the condiments was able to stimulate further food consumption, even after the subjects had “finished” their meals. New flavors and textures being presented to their meals provided the subjects more variety, allowing those additions to then weaken the sensory satiety of the subjects. This relates to what we already know about more ‘monotonous’ diets and their effectiveness when cravings and hunger are taken into account.
This serves as a great example of how food variety can easily alter our eating without us even realizing. As we know food variety can be good or bad depending on where it’s coming from, so being aware of where we get that variety while also considering our own goals and baseline habits is important to take note of regardless.
Brondel, L., Romer, M., Wymelbeke, V.V., et al. Variety enhances food intake in humans: role of sensory-specific satiety. Physiology and Behavior 2009; 97: 44-51.